The overall objective of this research project is the electrical stimulation of excitable tissue. The present investigation seeks to study the effectiveness of phrenic nerve stimulation in long term ventilatory support. This investigation has been divided into two major studies: a mechanical one concerned primarily with the development of a reliable electronic pacemaker for peripheral nerves, and a biological one concerned with 1) the pathologic effects of electrical stimulation on nerve tissue and 2) the physiologic response of the tissue to electrical stimulation. During the coming year we will evaluate diaphragm pacing in a few patients with some degree of intrinsic lung disease with and without added oxygen. We plan to continue recording the performance of integrated circuits placed in a water bath. Human implantation of the integrated circuit alternate pulse diaphragm pacemaker receiver (ABDC) may also be accomplished. Physiological evaluation of patients who are presently undergoing diaphragm pacing will continue. We are investigating direct spinal cord stimulation in the experimental animal at several sites. A stimulator to provide separate outputs of ABDC current for different tissue sites simultaneously is in the design stage. We plan to investigate new methods of encapsulating electronic components to be implanted in the body.